fix: treat C string literals and string_view as strings

[cursor]

Summary

The object(name, forward_range) constructor already excluded std::string (a range of char), but C string literals and std::string_view still matched it. That silently corrupted values:

object{"Name", "Papa"};              // was {"Name":[80,97,112,97,0]}
object{"Name", std::string_view{"Papa"}}; // was {"Name":[80,97,112,97]}

Fix

• Add StringLike for std::string / string_view / const char* / char*
• Exclude StringLike from the forward-range array constructor
• Construct/assign/builder::value string-like inputs as string_type
• Keep intentional vector<char> → integer array behavior

Test plan

• ./tools/CB.sh debug test --tags='[xson]' (432/432)
• New StringLikeConstructorNotCharArray regression covers literal, string_view, const char*, assignment, builder, and vector<char>

  

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Note

Medium Risk
Core JSON number parsing and object construction paths changed; behavior shifts for scientific notation and string-like literals, with broad test coverage but high impact on decode/round-trip correctness.

Overview
Fixes silent wrong doubles for scientific notation (e.g. 1e23 off by 1 ULP) by stopping base * std::pow(10, exp) at number completion. The decoder now records the raw number lexeme in m_number_token, then emit_parsed_number() uses std::from_chars for integers and doubles; finish_number() centralizes termination across integer, fraction, and exponent states. Large negative exponents are no longer rejected at the positive-exponent cap. Regression test ScientificNotationMatchesFromChars compares parse results to from_chars.

Separately, StringLike (const char*, char*, string_view) is excluded from the forward-range array constructor so object{"Name","Papa"} and similar no longer become ASCII code arrays (including a trailing NUL). Dedicated constructors, assignment, and builder::value coerce string-like inputs to string_type; vector<char> still builds byte arrays. Test StringLikeConstructorNotCharArray covers this.

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